Method and apparatus for detecting touch point of clutch

ABSTRACT

Disclosed are a method and an apparatus for detecting a touch point of a clutch and the method includes: maintaining a touch point of the clutch; correcting a setting value for determining a lowest value by calculating drag torque using a speed and an acceleration of a input shaft to change a detection range of the touch point; setting the lowest value of the speed of the input shaft within the changed detection range of the touch point to a reference value of the input shaft after actuating the clutch; releasing the clutch when the speed of the input shaft is more than a value acquired by adding the reference value of the input shaft and the corrected setting value for determining the lowest value; and updating the touch point as a clutch position matched to the reference value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No.10-2014-0121886 filed in the Korean Intellectual Property Office on Sep.15, 2014, and a U.S. patent application Ser. No. 14/565,402, filed Dec.9, 2014, each of which is incorporated herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to a method and an apparatus fordetecting a touch point of a clutch.

BACKGROUND ART

An automated manual transmission (AMT) or a double clutch transmission(DCT) has a clutch capable of automatically transmitting power by anactuator and when the clutch is used as a dry type, since a touch pointwhich is an actuation start point of the clutch is changed by a changein temperature of the clutch or abrasion, appropriate adjustment of thetouch point is required to maintain stable operability of the clutch.

FIG. 1 is a graph showing characteristics of clutch torque in respect toa stroke of a clutch actuator, in which when the stroke increases andreaches the touch point, the clutch torque starts to increase at lastand then, when a state of the clutch is normal, maximum clutch torquedesigned to be larger than maximum engine torque which an engine maytransfer in a maximum stroke may be transferred, but when the touchpoint moves due to the change in temperature of the clutch or theabrasion, the maximum engine torque may not be completely transferredeven in the maximum stroke.

Like this, the touch point is a primary factor that continuously stablymaintains an appropriate control relationship between the clutchactuator and the clutch and FIG. 2 is a diagram for describing a methodfor detecting and setting a touch point of a clutch in the related art,in which the method is performed while stopping or when a gear box isneutral directly after engine cranking.

That is, in the related art, the position of the clutch actuator isdetermined as the touch point at the time (B) when the clutch starts torotate by actuating the clutch actuator toward a direction in which theclutch is joined from a position in which the clutch is not joined (A)and the position is adjusted to a new touch point (C) and thereafter,the clutch actuator is actuated based on the newly set touch point.

To this end, in the related art, since the touch point of the clutch isdetected with respect to a change of angular acceleration of an inputshaft, the touch point of the clutch may be mis-detected depending on avariation of angular acceleration of the input shaft.

SUMMARY OF THE INVENTION

The present disclosure has been made in an effort to provide a methodand an apparatus for detecting a touch point of a clutch, which arecapable of improving controllability of the clutch with respect to achange in characteristics of the clutch by accurately detecting thetouch point of the clutch.

An exemplary embodiment of the present disclosure provides a method fordetecting a touch point of a clutch in a shift control module, themethod comprises: maintaining a touch point of the clutch; correcting asetting value for determining a lowest value by calculating drag torqueusing a speed and an acceleration of a input shaft to change a detectionrange of the touch point; setting the lowest value of the speed of theinput shaft within the changed detection range of the touch point to areference value of the input shaft after actuating the clutch; releasingthe clutch when the speed of the input shaft is more than a valueacquired by adding the reference value of the input shaft and thecorrected setting value for determining the inflection point; andupdating the touch point as a clutch position matched to the referencevalue.

In the changing of the detection range of the touch point, an upperlimit value of the clutch position is changed through the setting valuefor determining the lowest value is changed.

The upper limit value of the clutch position is proportional to thesetting value for determining the lowest value.

The updated touch point is a value acquired by subtracting a touch pointoffset value from the upper limit value of the clutch positioncorresponding to the corrected setting value for determining theinflection point.

The touch point offset value is proportional to a slope of the touchpoint.

Another exemplary embodiment of the present disclosure provides anapparatus for detecting a touch point of a clutch, the apparatuscomprising: a engine speed sensor configured to sense a speed and anacceleration of an input shaft; and a clutch control module configuredto correct a setting value for determining a lowest value by calculatingdrag torque using a speed and an acceleration of a input shaft to changea detection range of the touch point, set the lowest value of the speedof the input shaft within the changed detection range of the touch pointto a reference value of the input shaft after actuating the clutch,release the clutch when the speed of the input shaft is more than avalue acquired by adding the reference value of the input shaft and thecorrected setting value for determining the inflection point and updatethe touch point as a clutch position matched to the reference value.

The clutch control module changes an upper limit value of the clutchposition through the setting value for determining the lowest value ischanged.

The upper limit value of the clutch position is proportional to thesetting value for determining the lowest value.

The updated touch point is a value acquired by subtracting a touch pointoffset value from the upper limit value of the clutch positioncorresponding to the corrected setting value for determining theinflection point.

The touch point offset value is proportional to a slope of the touchpoint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing characteristics of clutch torque in respect toa stroke of a clutch actuator.

FIG. 2 is a diagram for describing a method for detecting and setting atouch point of a clutch in the related art.

FIG. 3 is a graph for describing a method for changing a detection rangeof a touch point depending on a speed and an acceleration of an inputshaft according to an exemplary embodiment of the present disclosure.

FIG. 4 is a block diagram illustrating a schematic internalconfiguration of an apparatus for detecting a touch point of a clutchaccording to an exemplary embodiment of the present disclosure.

FIG. 5 is a flowchart illustrating a method for detecting a touch pointof a clutch according to another exemplary embodiment of the presentdisclosure.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the disclosure. Thespecific design features of the present disclosure as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present disclosure throughout the several figures of the drawing.

DETAILED DESCRIPTION

It is noted that technical terms used in the specification are used tojust describe a specific exemplary embodiment and do not intend to limitthe present disclosure. Further, unless otherwise defined in thespecification, the technical terms used in the specification should beinterpreted as meanings generally appreciated by those skilled in theart and should not be interpreted as excessively comprehensive meaningsor excessively reduced meanings. Further, when the technical term usedin the specification is a wrong technical term that does not accuratelyexpress the spirit of the present disclosure, the technical term shouldbe understood by being substituted by a technical term which can becorrectly understood by those skilled in the art. In addition, a generalterm used in the present disclosure should be interpreted as defined ina dictionary or contextually, and should not be interpreted as anexcessively reduced meaning.

Unless otherwise apparently specified contextually, a singularexpression used in the specification includes a plural expression. Inthe specification, a term such as “comprising” or “including” should notbe interpreted as necessarily including all various components orvarious steps disclosed in the specification, and it should beinterpreted that some component or some steps among them may not beincluded or additional components or steps may be further included.

“Module” and “unit” which are suffixes for the components used in thespecification are granted or mixed by considering only easiness inpreparing the specification and do not have meanings or rolesdistinguished from each other in themselves.

Terms including ordinal numbers, such as ‘first’ and ‘second’, used inthe specification can be used to describe various components, but thecomponents should not be limited by the terms. The above terms are usedonly to discriminate one component from another component. For example,a first component may be named a second component and similarly, thesecond component may also be named the first component, withoutdeparting from the scope of the present disclosure.

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings, inwhich like reference numerals refer to like or similar elementsregardless of reference numerals and a duplicated description thereofwill be omitted.

In describing the present disclosure, when it is determined that thedetailed description of the publicly known art related to the presentdisclosure may obscure the gist of the present disclosure, the detaileddescription thereof will be omitted. Further, it is noted that theaccompanying drawings are only for easily understanding the spirit ofthe present disclosure and it should not be interpreted that the spiritof the present disclosure is limited by the accompanying drawings.

FIG. 3 is a graph for describing a method for changing a detection rangeof a touch point depending on a speed and an acceleration of an inputshaft according to an exemplary embodiment of the present disclosure.

Referring to FIG. 3, a setting value for determining a inflection pointsA and A′ represent a range for detecting the touch point and varydepending on drag torque calculated by using the speed and theacceleration of the input shaft (alternatively, a non-driving shaft).That is, reference numeral A represents the setting value fordetermining the inflection point before correction and reference numeralA′ represents the setting value for determining the inflection pointafter correction. The inflection points represent a lowest value of thespeed.

Meanwhile, an upper limit value of the clutch position is changedthrough the setting value for determining the lowest value is changed.As the setting value for determining the inflection points A and A′ arechanged, an upper limit value of the position (hereinafter, referred toas “clutch position”) of the clutch is changed, and reference numeral Crepresents an upper limit value of the clutch position corresponding tothe setting value for determining the inflection point A beforecorrection and reference numeral C′ represents the upper limit value ofthe clutch position corresponding to the setting value for determiningthe inflection point A′ after correction. That is, it can be seen thatthe larger the setting value for determining the inflection point is,the larger the upper limit value of the clutch position is, and thesmaller the setting value for determining the inflection point is, thesmaller the upper limit value of the clutch position is. The reason isthat the smaller a slope of the speed of the input shaft, that is, theacceleration of the input shaft is, the larger the drag torque is.

A reference value B of the input shaft as an inflection point representsthe lowest value of the speed of the input shaft and as illustrated inFIG. 3, the clutch position corresponding to the reference value B ofthe input shaft becomes the touch point.

As described above, in the exemplary embodiment of the presentdisclosure, as the detection range of the touch point is changeddepending on the speed and the acceleration of the input shaft, theaccuracy of the detection of the touch point may be increased.

FIG. 4 is a block diagram illustrating a schematic internalconfiguration of an apparatus for detecting a touch point of a clutchaccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 4, the apparatus for detecting a touch point of aclutch according to the present disclosure includes a throttle positionsensor 410, a vehicle speed sensor 420, an engine speed sensor 430, ashift control module 440, a clutch control module 450, a clutch actuator460, and a clutch 470.

The throttle position sensor 410 senses an opening angle of a throttlevalve (not illustrated).

The vehicle speed sensor 420 senses the speed of a vehicle.

The engine speed sensor 430 senses the speed and the acceleration of theinput shaft output from an engine (not illustrated).

The shift control module 440 determines whether a gear is shifted basedon the opening angle sensed by the throttle position sensor 410, thespeed of the vehicle sensed by the vehicle speed sensor 420, and thespeed of the input shaft sensed by the engine speed sensor 430.

In this case, when the gear is shifted, the shift control module 440transfers a shift command signal to the clutch control module 450,controls a shift motor (not illustrated) and a select motor (notillustrated) to shift the gear, and transfers a shift completion signalto the clutch control module 450 when the gear shifting is completed.

The clutch control module 450 controls the clutch actuator 460 accordingto the shift command signal and the shift completion signal receivedfrom the shift control module 440 to move the clutch position.

Meanwhile, the clutch control module 450 maintains a touch point of theclutch. The clutch control module 450 according to the presentdisclosure calculates the drag torque by using the speed and theacceleration of the input shaft sensed by the engine speed sensor 430 tocorrect the setting value for determining the inflection point andchanges the upper limit value of the clutch position depending on thecorrected setting value for determining the inflection point to changethe detection range of the touch point. In addition, the clutch controlmodule 450 sets the lowest value of the speed of the input shaft withinthe changed detection range of the touch point to a reference value ofthe input shaft and updates the touch point as a clutch position matchedto the reference value. The clutch control module 450 updates the clutchposition corresponding to the set reference value of the input shaft tothe touch point.

A detailed method in which the clutch control module 450 updates thetouch point as described above will be described with reference to FIG.5.

The clutch actuator 460 controls the clutch position according to thecontrol signal transferred from the clutch control module 450.

FIG. 5 is a flowchart illustrating a method for detecting a touch pointof a clutch according to another exemplary embodiment of the presentdisclosure.

Referring to FIG. 5, the clutch control module 450 verifies releasingthe input-shaft gear (S510) and thereafter, stores the speed and theacceleration of the input shaft when the input-shaft gear is released(S520).

The clutch control module 450 corrects the setting value for determiningthe inflection point by calculating the drag torque through the storedspeed and acceleration of the input shaft to change the detection rangeof the touch point (S530).

Subsequently, the clutch control module 450 actuates the clutch 470(S540) and thereafter, updates the lowest value of the speed of theinput shaft within the changed detection range of the touch point to thereference value of the input shaft (S550).

The clutch control module 450 determines whether the speed of the inputshaft is more than a value acquired by adding the updated referencevalue of the input shaft and the corrected setting value for determiningthe inflection point (S560) and releases the clutch 470 when the speedof the input shaft is more than the value acquired by adding the updatedreference value of the input shaft and the corrected setting value fordetermining the inflection point (S570).

Last, the clutch control module 450 updates the touch point (S580). Indetail, the clutch control module 450 updates the clutch positioncorresponding to the updated reference value of the input shaft to thetouch point. Herein, the updated touch point may be acquired bysubtracting a touch point offset value from the upper limit value of theclutch position corresponding to the corrected setting value fordetermining the inflection point. The touch point offset value may beset differently depending on the slope of the clutch position fordetecting the touch point. That is, since as the slope of the touchpoint is larger, an increase amount of the touch point up to anoccurrence time of the inflection point is larger, the touch pointoffset value may be set to a large value.

The aforementioned method may be implemented through various means. Forexample, the exemplary embodiments of the present disclosure may beimplemented by hardware, firmware, software, or combinations thereof.

When the exemplary embodiments of the present disclosure are implementedby the hardware, a method according to the exemplary embodiments of thepresent disclosure may be implemented by one or more ApplicationSpecific Integrated Circuits (ASICs), Digital Signal Processors (DSPs),Digital Signal Processing Devices (DSPDs), Programmable Logic Devices(PLDs), (Field Programmable Gate Arrays (FPGAs), processors,controllers, microcontrollers, and microprocessors.

When the exemplary embodiments of the present disclosure are implementedby the firmware or the software, the method according to the exemplaryembodiments of the present disclosure may be implemented in a module, aprocedure or a function that performs the aforementioned functions oroperations. A software code is stored in a memory unit to be driven bythe processor. The memory unit is positioned inside or outside theprocessor to transmit and receive data to and from the processor byvarious already known means.

As described above, the exemplary embodiments have been described andillustrated in the drawings and the specification. The exemplaryembodiments were chosen and described in order to explain certainprinciples of the disclosure and their practical application, to therebyenable others skilled in the art to make and utilize various exemplaryembodiments of the present disclosure, as well as various alternativesand modifications thereof. As is evident from the foregoing description,certain aspects of the present disclosure are not limited by theparticular details of the examples illustrated herein, and it istherefore contemplated that other modifications and applications, orequivalents thereof, will occur to those skilled in the art. Manychanges, modifications, variations and other uses and applications ofthe present construction will, however, become apparent to those skilledin the art after considering the specification and the accompanyingdrawings. All such changes, modifications, variations and other uses andapplications which do not depart from the spirit and scope of thedisclosure are deemed to be covered by the disclosure which is limitedonly by the claims which follow.

What is claimed is:
 1. A method for detecting a touch point of a clutch, the method comprising: calculating drag torque using a speed and an acceleration of an input shaft to change a detection range of the touch point; determining a lowest value of the speed of the input shaft within the changed detection range of the touch point; setting the lowest value to a reference value of the input shaft; and updating the touch point as a clutch position matched to the reference value.
 2. The method of claim 1, further comprising: releasing the clutch when the speed of the input shaft is greater than a value acquired by adding the reference value of the input shaft and a corrected setting value for determining the lowest value.
 3. The method of claim 1, further comprising: correcting a setting value for determining the lowest value.
 4. The method of claim 1, wherein an upper limit value of the clutch position is changed through the setting value when the lowest value is changed.
 5. The method of claim 4, wherein the upper limit value of the clutch position is proportional to the setting value for determining the lowest value.
 6. The method of claim 1, wherein the updated touch point is a value acquired by subtracting a touch point offset value from an upper limit value of the clutch position corresponding to a corrected setting value for determining the lowest value.
 7. The method of claim 6, wherein the touch point offset value is proportional to a slope of the touch point.
 8. An apparatus for detecting a touch point of a clutch, the apparatus comprising: a engine speed sensor configured to sense a speed and an acceleration of an input shaft; and a clutch control module configured to: calculate drag torque using a speed and an acceleration of an input shaft to change a detection range of the touch point; determine a lowest value of the speed of the input shaft within the changed detection range of the touch point; set the lowest value to a reference value of the input shaft; and update the touch point as a clutch position matched to the reference value.
 9. The apparatus of claim 8 is further configured to release the clutch when the speed of the input shaft is greater than a value acquired by adding the reference value of the input shaft and a corrected setting value for determining the lowest value.
 10. The apparatus of claim 8 is further configured to correct a setting value for determining the lowest value.
 11. The apparatus of claim 8, wherein an upper limit value of the clutch position is changed through the setting value when the lowest value is changed.
 12. The apparatus of claim 11, wherein the upper limit value of the clutch position is proportional to the setting value for determining the lowest value.
 13. The apparatus of claim 8, wherein the updated touch point is a value acquired by subtracting a touch point offset value from an upper limit value of the clutch position corresponding to a corrected setting value for determining the lowest value.
 14. The apparatus of claim 13, wherein the touch point offset value is proportional to a slope of the touch point. 